Question

In: Chemistry

Aluminum reacts with hydrochloric acid, but copper does not react with the acid. When a mixture...

Aluminum reacts with hydrochloric acid, but copper does not react with the acid. When a mixture of aluminum and copper having a mass of 0.3579 grams is combined with excess hydrochloric acid, 315.50 mL of hydrogen gas, measured over water, is generated. The temperature at the time of collection is 27.3 oC (vapor pressure of water at 27.3 oC = 27.214 torr), and the total pressure in the collection container is 764.1 torr. Determine the mass percentage of aluminum in the original mixture.

I've pretty much got my chem exam down for tomorrow, but I really need guidance for this question. Please show work and explain what you did (doesn't have to be so detailed).

Solutions

Expert Solution

Total pressure is 764.1 torr

vapor pressure of water at 27.3 oC = 27.214 torr

Therefore pressure for hydrogen = 764.1 torr - 27.214 torr = 736.886 torr = (736.886 / 760) atm

vilume of hydrogen evolved = 315.50 mL = 315.50 x 10-3 L

T = 27.3 oC = 273 + 27.3 = 300.3 K

Gas onstant R = 0.082 L atm K?1 mol?1

Now PV = nRT where n = number of moles

or n = PV/ RT

therefore number of moles of hydrogen evolved

= (736.886 / 760) atm x 315.50 x 10-3 L / 0.082 L atm K?1 mol?1 x 300.3 K = 12.42 x 10-3 mol

Now the reaction between Al and HCl is

2Al + 6HCl ----> 2AlCl3 + 3H2

So 3 moles of hydrogen is produced from 2 moles of Al

so 12.42 x 10-3 moles of hydrogen is produced from 2 x 12.42 x 10-3 / 3 moles of Al = 8.28 x 10-3 moles of Al

Now 1 mole of Al has mass 26.982 g

so 8.28 x 10-3 moles of Al has mass 26.982 x 8.28 x 10-3 g = 0.2234 g

Therefore mass % of Al in the mixture = (0.2234/ 0.3579) x 100 = 62.24 %


Related Solutions

Aluminum reacts with excess hydrochloric acid to form aqueous aluminum chloride and hydrogen gas. The resulting...
Aluminum reacts with excess hydrochloric acid to form aqueous aluminum chloride and hydrogen gas. The resulting gas is collected over water and it measured to have 218.6 ml at 26°C and 0.947 atm. If the vapor pressure of water is 25.2 mmHg at 26ºC, how many grams of aluminum reacted? Air is about 78.0% nitrogen molecules and 21.0% oxygen molecules. Several other gases make up the remaining 1% of air molecules. What is the partial pressure of nitrogen in air...
Aluminum reacts with excess hydrochloric acid to form aqueous aluminum chloride and 30.6 mL of hydrogen...
Aluminum reacts with excess hydrochloric acid to form aqueous aluminum chloride and 30.6 mL of hydrogen gas over water at 27°C and 751 mmHg. How many grams of aluminum reacted? The partial pressure of water at 27°C is 26.8 mmHg.
What are the spectator ions when hydrochloric acid reacts with sodium hydroxide? a) Na + and...
What are the spectator ions when hydrochloric acid reacts with sodium hydroxide? a) Na + and H + b) Cl – and OH – c) H + and OH – d) Na + and Cl –
A.) Identify the one substrate that reacts the fastest when treated with hydrochloric acid at room...
A.) Identify the one substrate that reacts the fastest when treated with hydrochloric acid at room temperature. A.) 5-Chloro-2-methylheptan-2-ol B.) 6-Chloro-6-methylheptan-3-ol C.) 2-Chloro-2-methylheptan-1-ol D.) 2-Chloro-2-methylheptan-3-ol B.) identify the one substrate that reacts the fastest when treated with PBr3. A.) 4-Methyl-3-penten-1-ol B.) 3-Methyl-2-buten-1-ol C.) 6-Methyl-5-hepten-2-ol D.) 2,4-Dimethyl-2-hepten-4-ol please help!!!
14. a) What is the product when you react hydrochloric acid with metal? b) What is...
14. a) What is the product when you react hydrochloric acid with metal? b) What is the product when you react hydrochloric acid with carbonates? c) What is the product when you react hydrochloric acid with ammonia? d) What is the product when you react hydrochloric acid with hydroxide? e) Which of the reaction in a) through d) is most similar to the reaction which produces Benadryl? (look up an image of the ingredient label)
When 200. mL of 0.40 M hydrochloric acid solution is mixed with 3.76 g of aluminum...
When 200. mL of 0.40 M hydrochloric acid solution is mixed with 3.76 g of aluminum metal, how many moles of hydrogen gas would be produced? 6HCl(aq) + 2Al(s) → 2AlCl3(aq) + 3H2(g)
1.         When solid calcium carbonate reacts with hydrochloric acid, three products result. a) Write the balanced...
1.         When solid calcium carbonate reacts with hydrochloric acid, three products result. a) Write the balanced equation to represent this reaction. b) How many grams of calcium carbonate will fully react with 75.0 mL of HCl (density = 1.00 g/mL)? c) When 25.2 grams of calcium carbonate is mixed with 65.0 mL HCl, which reactant is limiting? d) Using the information obtained in c), how many grams of calcium chloride will be produced? e) How many grams of the excess...
When 0.0425 g of magnesium metal were allowed to react with excess hydrochloric acid, 45.80 mL...
When 0.0425 g of magnesium metal were allowed to react with excess hydrochloric acid, 45.80 mL of hydrogen gas were collected over water. The barometric pressure at the time was reported to be 29.78 in Hg. The temperature of the water near the mouth of the eudiometer was 25.1oC. The water level inside the tube was measured to be 25.24 cm higher than the water level in the beaker. (g) What is the molar gas volume at STP as determined...
61.) Consider the neutralization reaction that takes place when hydrochloric acid reacts with solid nickel(II) carbonate....
61.) Consider the neutralization reaction that takes place when hydrochloric acid reacts with solid nickel(II) carbonate. a. Write a conversion factor that relates moles of HCl to moles of NiCO3 for this reaction. b. What is the minimum volume of 6.0 M HCl necessary to react completely with 14.266 g of solid nickel(II) carbonate, NiCO3?
If 0.032g impure sample of aluminum is reacted with an excess of hydrochloric acid producing 32.4...
If 0.032g impure sample of aluminum is reacted with an excess of hydrochloric acid producing 32.4 mL of hydrogen gas, what is the percent purity of the aluminum if the hydrogen gas was collected over water at a temperature of 24.0 celcius and a pressure of 742 mmHg
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT